Transcatheter mitral valve stent frames

ABSTRACT

A prosthetic heart valve may include a stent having an inflow end, an outflow end, a collapsed condition, and an expanded condition. The prosthetic valve may also include a collapsible and expandable valve assembly disposed within the stent and having a plurality of leaflets. The prosthetic valve and/or stent may include features to anchor the prosthetic valve to a native valve annulus and to seal the prosthetic valve with respect to the native valve annulus, such as planar and/or nonplanar annular sealing members coupled to ends of the stent. The stent may include one or more circumferential rows of anchor members or hooks extending radially outwardly from the stent. These hooks may be configured to extend in a particular direction when the stent is in the collapsed condition to facilitate resheathing of the stent if, upon deployment, a user determines the prosthetic heart valve is not positioned optimally.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application claims the benefit of the filing date of U.S.Provisional Patent Application No. 61/970,443 filed Mar. 26, 2014, thedisclosure of which is hereby incorporated herein by reference.

BACKGROUND

The present disclosure relates to heart valve replacement and, inparticular, to collapsible prosthetic heart valves. More particularly,the present disclosure relates to designs for stent frames forcollapsible prosthetic heart valves.

Prosthetic heart valves that are collapsible to a relatively smallcircumferential size can be delivered into a patient less invasivelythan valves that are not collapsible. For example, a collapsible valvemay be delivered into a patient via a tube-like delivery apparatus suchas a catheter, a trocar, a laparoscopic instrument, or the like. Thiscollapsibility can avoid the need for a more invasive procedure such asfull open-chest, open-heart surgery.

Collapsible prosthetic heart valves typically take the form of a valvestructure mounted on a stent. There are two types of stents on which thevalve structures are ordinarily mounted: a self-expanding stent and aballoon-expandable stent. To place such valves into a delivery apparatusand ultimately into a patient, the valve is generally first collapsed orcrimped to reduce its circumferential size.

When a collapsed prosthetic valve has reached the desired implant sitein the patient (e.g., at or near the annulus of the patient's heartvalve that is to be replaced by the prosthetic valve), the prostheticvalve can be deployed or released from the delivery apparatus andre-expanded to full operating size. For balloon-expandable valves, thisgenerally involves releasing the entire valve, assuring its properlocation, and then expanding a balloon positioned within the valvestent. For self-expanding valves, on the other hand, the stentautomatically expands as the sheath covering the valve is withdrawn.

BRIEF SUMMARY

According to one embodiment of the disclosure, a prosthetic heart valvemay include a stent having an inflow end, an outflow end, a centerportion between the inflow end and the outflow end, a collapsedcondition, and an expanded condition. A collapsible and expandable valveassembly may be disposed within the stent and may have a plurality ofleaflets. A first annular sealing member may be coupled to the inflowend and a second annular sealing member may be coupled to the outflowend.

According to another embodiment of the disclosure, a stent having anexpanded condition and a collapsed condition may include a substantiallycylindrical body having a first end and a second end. A flared portionmay be coupled to the first end of the body and may extend radiallyoutwardly from the body and away from the second end of the body whenthe stent is in the expanded condition. A plurality of anchor membersmay each have a first end coupled to the body and a second free endextending radially outwardly from the body and toward the first end ofthe body when the stent is in the expanded condition. The flared portionand the second free ends of the anchor members may be configured toextend away from the second end of the body when the stent is in thecollapsed condition.

According to a further embodiment of the disclosure, a stent having anexpanded condition and a collapsed condition may include a substantiallycylindrical center body having a first end and a second end. A firstplurality of anchor members may each have a first end coupled to thefirst end of the body and a second free end extending radially outwardlyfrom the body and toward the second end of the body when the stent is inthe expanded condition. A second plurality of anchor members may eachhave a first end coupled to the body and a second free end extendingradially outwardly from the body and toward the second end of the bodywhen the stent is in the expanded condition. The first and secondplurality of anchor members may be configured to extend toward thesecond end of the body when the stent is in the collapsed condition.

According to still another embodiment of the disclosure, a stent havingan expanded condition and a collapsed condition may include asubstantially cylindrical center body having a first end and a secondend. A first plurality of anchor members each having a first end coupledto the body and a second free end may extend radially outwardly from thebody and toward the first end of the body when the stent is in theexpanded condition. A second plurality of anchor members each having afirst end coupled to the first end of the body and a second free end mayextend radially outwardly from the body and toward the second end of thebody when the stent is in the expanded condition. The first plurality ofanchor members may extend toward the first end of the body and thesecond plurality of anchor members may extend toward the second end ofthe body when the stent is in the collapsed condition.

According to yet another embodiment of the disclosure, a stent having anexpanded condition and a collapsed condition may include a substantiallycylindrical center body having a first end, a second end, and alongitudinal axis extending between the first end and the second end. Afirst plurality of anchor members may each have a first end coupled tothe body and a second free end extending radially outwardly from thebody and substantially perpendicular to the longitudinal axis of thebody when the stent is in the expanded condition. A second plurality ofanchor members may each have a first end coupled to the body and asecond free end extending radially outwardly from the body andsubstantially perpendicular to the longitudinal axis of the body whenthe stent is in the expanded condition. The first plurality of anchormembers may extend away from the second end of the body and the secondplurality of anchor members may extend away from the first end of thebody when the stent is in the collapsed condition.

According to yet a further embodiment of the disclosure, a prostheticheart valve may include a stent having an inflow end, an outflow end, acollapsed condition, and an expanded condition. The stent may be formedfrom wire and may have a first series of hooks and a second serieshooks. A cuff may be coupled to the stent. When the stent is in theexpanded condition, each hook of the first series may extend radiallyoutwardly from the stent at the inflow end and each hook of the secondseries may include a first portion that extends radially outwardly fromthe stent at the outflow end and a second portion that extends towardthe inflow end.

According to an even further embodiment of the disclosure, a prostheticheart valve may include a stent having an inflow end, an outflow end, acollapsed condition, and an expanded condition. The stent may be formedof a plurality of struts. A collapsible and expandable valve assemblymay be disposed within the stent and may have a plurality of leaflets. Acommissure attachment feature may be attached to at least one of theplurality of struts and may be positioned between the inflow end and theoutflow end when the stent is in the expanded condition.

BRIEF DESCRIPTION OF THE DRAWINGS

Various embodiments of the present disclosure are described herein withreference to the drawings, wherein:

FIG. 1 is a schematic cutaway representation of a human heart showing atransapical delivery approach;

FIG. 2 is a schematic representation of a native mitral valve andassociated cardiac structures;

FIG. 3A is a side view of a prosthetic heart valve according to theprior art;

FIG. 3B is a longitudinal cross-section of the prosthetic heart valve ofFIG. 3A;

FIG. 4A is a schematic perspective view of a prosthetic heart valveaccording to the present disclosure;

FIG. 4B is a longitudinal cross-section of the prosthetic heart valve ofFIG. 4A;

FIG. 4C is a schematic representation of the prosthetic heart valve ofFIG. 4A disposed in a native valve annulus;

FIG. 5A is a schematic cut-away perspective view of another prostheticheart valve according to the present disclosure;

FIG. 5B is a longitudinal cross-section of the prosthetic heart valve ofFIG. 5A;

FIG. 5C is a schematic representation of the prosthetic heart valve ofFIG. 5A disposed in a native valve annulus;

FIG. 6A is a schematic perspective view of a docking station for usewith a prosthetic heart valve;

FIG. 6B is a cross-sectional view of the docking station of FIG. 6A;

FIG. 6C is a schematic representation of the docking station of FIG. 6Adisposed in a native valve annulus with a prosthetic heart valvedisposed within the docking station.

FIG. 7A is a perspective view of a stent of a prosthetic heart valveaccording to the present disclosure;

FIG. 7B is a schematic representation of the stent of FIG. 7A disposedin a native valve annulus;

FIG. 7C is a perspective view of another stent of a prosthetic heartvalve according to the present disclosure;

FIG. 7D is a schematic representation of the stent of FIG. 7C disposedin a native valve annulus;

FIG. 8A is a side view of another stent of a prosthetic heart valveaccording to the present disclosure;

FIG. 8B is a schematic representation of the stent of FIG. 8A disposedin a native valve annulus;

FIG. 9 is a developed view of a further stent of a prosthetic heartvalve according to the present disclosure;

FIG. 10 is a perspective view of yet another stent of a prosthetic heartvalve according to the present disclosure;

FIG. 11 is a perspective view of another prosthetic heart valveaccording to the present disclosure;

FIG. 12 is a side view of a further prosthetic heart valve according tothe present disclosure; and

FIG. 13 is a perspective view of still another stent of a prostheticheart valve according to the present disclosure.

Various embodiments of the present disclosure will now be described withreference to the appended drawings. It is to be appreciated that thesedrawings depict only some embodiments of the disclosure and aretherefore not to be considered limiting of its scope.

DETAILED DESCRIPTION

Blood flows through the mitral valve from the left atrium to the leftventricle. As used herein, the term “inflow end,” when used inconnection with a prosthetic mitral heart valve, refers to the end ofthe heart valve closest to the left atrium when the heart valve isimplanted in a patient, whereas the term “outflow end,” when used inconnection with a prosthetic mitral heart valve, refers to the end ofthe heart valve closest to the left ventricle when the heart valve isimplanted in a patient. Further, when used herein with reference to adelivery device, the terms “proximal” and “distal” are to be taken asrelative to a user using the device in an intended manner. “Proximal” isto be understood as relatively close to the user and “distal” is to beunderstood as relatively farther away from the user. Also, as usedherein, the terms “substantially,” “generally,” and “about” are intendedto mean that slight deviations from absolute are included within thescope of the term so modified. Generally, materials described as beingsuitable for components in one embodiment may also be suitable forsimilar components described in other embodiments.

FIG. 1 is a schematic cutaway representation of human heart 100. Thehuman heart includes two atria and two ventricles: right atrium 112 andleft atrium 122, and right ventricle 114 and left ventricle 124. Heart100 further includes aorta 110, and aortic arch 120. Disposed betweenthe left atrium and the left ventricle is mitral valve 130. Mitral valve130, also known as the bicuspid valve or left atrioventricular valve, isa dual-flap that opens as a result of increased pressure in left atrium122 as it fills with blood. As atrial pressure increases above that ofleft ventricle 124, mitral valve 130 opens and blood passes into leftventricle 124. Blood flows through heart 100 in the direction shown byarrows “B”.

A dashed arrow, labeled “TA”, indicates a transapical approach ofimplanting a prosthetic heart valve, in this case to replace the mitralvalve. In transapical delivery, a small incision is made between theribs and into the apex of left ventricle 124 to deliver the prostheticheart valve to the target site. A second dashed arrow, labeled “TS”,indicates a transseptal approach of implanting a prosthetic heart valvein which the valve is passed through the septum between right atrium 112and left atrium 122. Other approaches for implanting a prosthetic heartvalve are also possible.

FIG. 2 is a more detailed schematic representation of native mitralvalve 130 and its associated structures. As previously noted, mitralvalve 130 includes two flaps or leaflets, posterior leaflet 136 andanterior leaflet 138, disposed between left atrium 122 and leftventricle 124. Cord-like tendons, known as chordae tendineae 134,connect the two leaflets 136, 138 to the medial and lateral papillarymuscles 132. During atrial systole, blood flows from higher pressure inleft atrium 122 to lower pressure in left ventricle 124. When leftventricle 124 contracts in ventricular systole, the increased bloodpressure in the chamber pushes leaflets 136, 138 to close, preventingthe backflow of blood into left atrium 122. Since the blood pressure inleft atrium 122 is much lower than that in left ventricle 124, leaflets136, 138 attempt to evert to the low pressure regions. Chordae tendineae134 prevent the eversion by becoming tense, thus pulling on leaflets136, 138 and holding them in the closed position.

FIGS. 3A and 3B are a side view and a longitudinal cross-sectional viewof prosthetic heart valve 300 according to the prior art. Prostheticheart valve 300 is a collapsible prosthetic heart valve designed toreplace the function of the native mitral valve of a patient (see nativemitral valve 130 of FIGS. 1-2). Generally, prosthetic valve 300 has asubstantially cylindrical shape with inflow end 310 and outflow end 312.When used to replace native mitral valve 130, prosthetic valve 300 mayhave a low profile so as not to interfere with atrial function in thenative valve annulus.

Prosthetic heart valve 300 may include stent 350, which may be formedfrom biocompatible materials that are capable of self-expansion, suchas, for example, shape memory alloys including Nitinol. Stent 350 mayinclude a plurality of struts 352 that form cells 354 connected to oneanother in one or more annular rows around the stent. Cells 354 may allbe of substantially the same size around the perimeter and along thelength of stent 350. Alternatively, cells 354 near inflow end 310 may belarger than the cells near outflow end 312. Stent 350 may be expandableto provide a radial force to assist with positioning and stabilizingprosthetic heart valve 300 in the native valve annulus.

Prosthetic heart valve 300 may also include a substantially cylindricalvalve assembly 360 including a pair of leaflets 362 (FIG. 3B) attachedto a cuff 364 (FIG. 3A). Leaflets 362 replace the function of nativemitral valve leaflets 136 and 138 described above with reference to FIG.2. That is, leaflets 362 coapt with one another to function as a one-wayvalve. Though prosthetic heart valve 300 is illustrated as having avalve assembly 360 with two leaflets 362, it will be appreciated thatprosthetic heart valve 300 may have more than two leaflets when used toreplace the mitral valve or other cardiac valves within a patient. Bothcuff 364 and leaflets 362 may be wholly or partly formed of any suitablebiological material, such as bovine or porcine pericardium, or polymers,such as polytetrafluoroethylene (PTFE), urethanes and the like. Valveassembly 360 may be secured to stent 350 by suturing to struts 352 or byusing tissue glue, ultrasonic welding or other suitable methods.

When prosthetic heart valve 300 is implanted in a patient, for exampleat the annulus of native mitral valve 130, it is biased towards anexpanded condition, providing radial force to anchor the valve in place.However, if the radial force is too high, damage may occur to hearttissue. If, instead, the radial force is too low, the heart valve maymove from its implanted position, for example, into either leftventricle 124 or left atrium 122, requiring emergency surgery to removethe displaced valve. The potential for such movement may be heightenedin mitral valve applications, particularly if a low profile valve isused.

Another potential issue with prosthetic heart valves is inadequatesealing between the prosthetic valve and the native tissue. For example,if prosthetic heart valve 300 is implanted at the annulus of mitralvalve 130 in a patient, improper or inadequate sealing may result inblood flowing from left ventricle 124 into left atrium 122, even ifleaflets 362 of valve assembly 360 are working properly. This may occur,for example, if blood flows in a retrograde fashion between the outerperimeter of prosthetic heart valve 300 and the native tissue at thesite of implantation. This phenomenon is known as perivalvular (orparavalvular) leak (“PV leak”).

FIGS. 4A and 4B illustrate a prosthetic heart valve 400 according to oneembodiment of the disclosure in perspective and longitudinalcross-section views, respectively. Prosthetic heart valve 400 is acollapsible prosthetic heart valve designed to replace the function ofthe native mitral valve of a patient. Generally, prosthetic valve 400has inflow end 410 and outflow end 412.

Prosthetic heart valve 400 may include stent 450, which may be formedfrom biocompatible materials that are capable of self-expansion, suchas, for example, shape memory alloys including Nitinol. Stent 450 mayinclude a plurality of struts 452 that form cells 454 connected to oneanother in one or more annular rows around the stent. Stent 450 may beradially expandable to provide a radial force to assist with positioningand stabilizing prosthetic heart valve 400 in the native mitral valveannulus. Stent 450 may be substantially cylindrically shaped when in theexpanded condition.

Prosthetic heart valve 400 may also include valve assembly 460 includinga pair of leaflets 462. Leaflets 462 function similarly to leaflets 362described above in connection with FIG. 3B, and more or fewer leafletsmay be used in other applications.

A number of sealing elements may be provided on prosthetic heart valve400. In particular, prosthetic heart valve 400 may include a firstsealing ring 480 positioned at inflow end 410 and a second sealing ring490 positioned at outflow end 412. Each sealing ring 480, 490 may beformed of a biocompatible material that allows tissue ingrowth. Forexample, sealing rings 480 and 490 may be formed of fabrics and/orpolymers, such as polytetrafluoroethylene (PTFE), urethanes and thelike. Alternatively, sealing rings 480 and 490 may be formed oftraditional stent materials, such as shape memory alloys includingNitinol, and may take forms including Nitinol coils. In still otherembodiments, sealing rings 480 and 490 may be formed from a metal orpolymer mesh or braid. Still further, sealing rings 480, 490 may beformed of tissue, such as porcine cardiac tissue. Some or all of theabove materials may be used in combination with a coating, such as acollagen coating, a fibrin coating, or a polymer coating (such as asilicone coating). Sealing rings 480 and 490 may be attached to inflowend 410 and outflow end 412, respectively, by, for example, sutures,adhesives, ultrasonic welding or other suitable methods. Alternatively,if sealing rings 480 and 490 are formed of the same material as stent450, sealing rings 480 and 490 may be formed integrally with stent 450.

Each sealing ring 480, 490 is generally annular, with a center portionof each sealing ring being attached to stent 450 so that blood may flowthrough the stent. Sealing rings 480 and 490 may each have an outerdiameter that is greater than the diameter of stent 450 when in theexpanded condition. When stent 450 is in the expanded condition, sealingrings 480 and 490 each have a substantially planar configuration.However, other shapes and sizes may be suitable depending on theparticular anatomy of the patient. FIG. 4C shows prosthetic heart valve400 implanted within native valve annulus VA between left atrium 122 andleft ventricle 124. In the implanted position, first sealing ring 480 ispositioned on the atrial side of native valve annulus VA while secondsealing ring 490 is positioned on the ventricular side of native valveannulus VA. Sealing rings 480 and 490 may help prevent PV leak bypreventing blood from flowing from left ventricle 124 to left atrium 122between the native valve annulus VA and the outer perimeter ofprosthetic heart valve 400. This function may be enhanced once tissuebegins to grow into first sealing ring 480 and second sealing ring 490.

In addition to helping prevent PV leak, sealing ring 480 may provide ananchoring effect, helping to prevent prosthetic heart valve 400 frommigrating toward left ventricle 124. Similarly, second sealing ring 490may also provide an anchoring effect, helping to prevent prostheticheart valve 400 from migrating toward left atrium 122. This additionalanchoring ability may reduce the radial force required of stent 450 tokeep prosthetic heart valve 400 secured in native valve annulus VA,which, in turn, may allow stent 450 to have a smaller fully expandeddiameter than traditional stents. This reduction in size may bepossible, in part, due to a reduction or elimination of the need to havea relatively large stent frame to maximize the range of anatomies whichcould accept the stent and still have enough radial force to hold thestent in place. The relatively smaller diameter which may be possibledue to the above-described features may result in lower hydrodynamicload on prosthetic heart valve 400, which may reduce the stresses onvalve assembly 460 and which also may reduce the strain on the materialforming stent 450.

FIGS. 5A and 5B illustrate a prosthetic heart valve 500 according toanother embodiment of the disclosure. Prosthetic heart valve 500 issimilar to prosthetic heart valve 400 in certain respects. For example,prosthetic heart valve 500 may include stent 550, which may be formedfrom biocompatible materials that are capable of self-expansion, suchas, for example, shape memory alloys including Nitinol. Stent 550 mayinclude a plurality of struts 552 that form cells 554 connected to oneanother in one or more annular rows around the stent. Stent 550 may beradially expandable to provide a radial force to assist with positioningand stabilizing prosthetic heart valve 500 in the native valve annulus.Stent 550 has the general shape of a cylinder, except that it is bowedinwardly from inflow end 510 and outflow end 512 toward the center. Inother words, stent 550 has a concave shape, wherein the center of stent550 has a smaller diameter than that of inflow end 510 and outflow end512 when in the expanded condition.

Prosthetic heart valve 500 may also include valve assembly 560 includinga pair of leaflets 562. Leaflets 562 function similarly to leaflets 362described above in connection with FIG. 3B, and more or fewer leafletsmay be used in other applications.

Prosthetic heart valve 500 may also include a number of sealingelements. In particular, prosthetic heart valve 500 may include a firstsealing ring 580 positioned at inflow end 510 and a second sealing ring590 positioned at outflow end 512. Sealing rings 580, 590 may begenerally similar to sealing rings 480, 490, with the exception thatfirst sealing ring 580 is curved toward outflow end 512 and secondsealing ring 590 is curved toward inflow end 510. In other words,sealing rings 580 and 590 are substantially non-planar when stent 550 isin the expanded condition. Sealing rings 580, 590 may be formed of thesame biocompatible materials described above for forming sealing rings480 and 490, and may be attached to inflow end 510 and outflow end 512,respectively, in the same manner as sealing rings 480 and 490.

Each sealing ring 580, 590 is generally annular, with a center portionof each sealing ring being attached to stent 550 so that blood may flowthrough the stent. As described above, sealing rings 580, 590 may becurved away from the ends of stent 550 to which the rings are attached.In other words, the outer perimeter of first sealing ring 580 is closerto outflow end 512 than the inner perimeter of that sealing ring.Similarly, the outer perimeter of second sealing ring 590 is closer toinflow end 510 than the inner perimeter of that sealing ring. However,other shapes and sizes may be suitable depending on the particularanatomy of the patient.

FIG. 5C shows prosthetic heart valve 500 implanted within native valveannulus VA between left atrium 122 and left ventricle 124. In theimplanted position, first sealing ring 580 is positioned on the atrialside of native valve annulus VA while second sealing ring 590 ispositioned on the ventricular side of native valve annulus VA. In thesepositions, sealing rings 580 and 590 mitigate PV leak by preventingblood from flowing from left ventricle 124 to left atrium 122 betweenthe native valve annulus VA and the outer perimeter of prosthetic heartvalve 500. Once tissue begins to grow into first sealing ring 580 andsecond sealing ring 590, PV leak may be mitigated to an even greaterextent.

In addition to helping prevent PV leak, first sealing ring 580 mayprovide an anchoring effect, helping to prevent prosthetic heart valve500 from migrating toward left ventricle 124. Similarly, second sealingring 590 may also provide an anchoring effect, helping to preventprosthetic heart valve 500 from migrating toward left atrium 122. Thecurvature of sealing rings 580 and 590 may dictate, in part, howprosthetic heart valve 500 interacts with the anatomy and how stressesare distributed in valve 500. The above-described curvature may have anenhanced effect on sealing and anchoring in comparison to a relativelyflat or planar sealing ring. This may be due, in part, to the anatomynear the implant site having generally non-planar surfaces. Further, thecurvature of sealing rings 580 and 590 may effectively pinch tissue ofthe annulus resulting in enhanced sealing and anchoring, while alsoincreasing apposition to the annulus by forcing any irregular anatomicgeometries into the pinched area. In addition, the inwardly bowed shapeof stent 550 may provide a greater contact area between stent 550 andthe native valve annulus VA.

FIGS. 6A and 6B illustrate a prosthetic heart valve docking station 600according to one embodiment of the disclosure in perspective andlongitudinal cross-sectional views, respectively. As is described below,docking station 600 may first be implanted in a native valve annulus,and a prosthetic heart valve may be subsequently implanted in dockingstation 600.

Docking station 600 has inflow end 610 and outflow end 612, and may beformed from biocompatible materials that are capable of self-expansion,such as, for example, shape memory alloys including Nitinol. Dockingstation 600 may alternatively be made of a material that is notself-expandable, such as stainless steel, which may be expanded with theuse of a separate expandable structure, such as a balloon.

Docking station 600 may have the general form of a hollow tube with acylindrical center section 670 and anchoring members extending radiallyoutwardly at inflow end 610 and outflow end 612. For example, theillustrated embodiment of docking station 600 includes first anchor rim680 and second anchor rim 690. The particular shape of each anchor rim680, 690 may be varied. For example, first anchor rim 680 may have acylindrical outer surface 682 that is substantially concentric tocylindrical center section 670. One end surface 684 of anchor rim 680coextensive with inflow end 610 may lie in a plane perpendicular to theaxis of rotation of central section 670. The other end surface 686 ofanchor rim 680 may be inclined at an oblique angle to the axis ofrotation of central section 670. Second anchor rim 690 may have asimilar structure. That is, second anchor rim 690 may have a cylindricalouter surface 692 that is substantially concentric to center section670. One end surface 694 of anchor rim 690 coextensive with outflow end612 may lie in a plane perpendicular to the axis of rotation of centersection 670, while the other end surface 696 of anchor rim 690 may beinclined at an oblique angle to that axis of rotation. The inclinedsurfaces of anchor rims 680 and 690 may provide better contact with anative valve annulus, but may be varied and still be within the scope ofthis disclosure.

FIG. 6C shows docking station 600 implanted within native valve annulusVA between left atrium 122 and left ventricle 124. In the implantedposition, first anchor rim 680 is positioned on the atrial side ofnative valve annulus VA while anchor rim 690 is positioned on theventricular side of native valve annulus VA. Anchor rims 680 and 690 mayprovide an anchoring effect, helping prevent docking station 600 frommigrating toward left ventricle 124 or left atrium 122. Once dockingstation 600 has been implanted as described, prosthetic heart valve PHVmay be assembled to the docking station.

A number of benefits may result from using a two-step process in whichdocking station 600 is first implanted within native valve annulus VAand then prosthetic heart valve PHV is assembled to docking station 600.For example, when implanted, prosthetic heart valve PHV, which may takethe form of any traditional prosthetic heart valve or any of theembodiments disclosed herein, will encounter a predictable environment.That is, the variability in anatomy from one patient to another willhave less effect on the positioning and functioning of prosthetic heartvalve PHV, because prosthetic heart valve PHV will interact directlywith docking station 600 rather than with the anatomy of native valveannulus VA.

FIG. 7A illustrates a stent 700 of a prosthetic heart valve according toone embodiment of the disclosure. Stent 700 is collapsible andexpandable for use in a prosthetic heart valve intended to replace thefunction of the native mitral valve of a patient. In FIG. 7A, stent 700is illustrated in its expanded condition. The remaining components thatwould be attached to stent 700 to form a prosthetic heart valve, such asleaflets and a cuff, are omitted from the figures for clarity.

Stent 700 has inflow end 710 and outflow end 712, and may be formed frombiocompatible materials that are capable of self-expansion, such as, forexample, shape memory alloys including Nitinol. Stent 700 may include aplurality of struts 752 that form cells connected to one another in oneor more annular rows around the stent.

Stent 700 may be thought of as having at least three main portions. Atinflow end 710 is flared portion 770, which flares radially outwardly ina direction away from outflow end 712. Flared portion 770 may includeone or more circumferential rows of relatively small cells 754 a. Eachcell 754 a is formed from a group of struts 752 that defines a geometricshape having a relatively small area, in this case generally a diamondshape.

Stent 700 also includes a substantially cylindrical body 780 thatextends from flared portion 770 to outflow end 712 of the stent. Body780 may include one or more circumferential rows of relatively largecells 754 b. Each cell 754 b is formed from a group of struts 752 thatdefines a geometric shape having a relatively large area, in this casegenerally a diamond shape. Struts 752 forming larger cells 754 b may bethicker and stronger than struts 752 forming smaller cells 754 a. Rowsof relatively small cells 754 a may be thought of as being ahigh-density arrangement of cells, while rows of relatively large cells754 b may be thought as being a low-density arrangement of cells.

Stent 700 also includes a portion with anchor members, in this casehooks 790. Hooks 790 are formed of struts 752 that extend radiallyoutwardly toward inflow end 710. Hooks 790 may be integral with stent700, being formed from the same single piece of starting material, andmay be connected to stent 700 anywhere on body 780. It should be notedthat the term hooks may include other anchoring structures, for examplebarbs or clips.

When being used in a prosthetic heart valve for replacing the nativemitral valve of a patient, stent 700 is crimped to a collapsed conditionand positioned within a catheter or similar structure of a deliverydevice. The delivery device may, for example, be inserted through theapex of the heart (transapical delivery) or through the femoral arteryand passed through the vasculature to the implant site (transfemoraldelivery). Once the delivery device is near the site of implantation,the sheath or other member compressing stent 700 may be slowly retractedto reveal stent 700 and allow it to expand to the expanded condition. Ifa transapical method is used with a split sheath, as a proximal portionof the sheath is retracted proximally, hooks 790 are first released fromthe proximal portion of the sheath and expand. The release of hooks 790may be performed in left ventricle 124 and then pushed distally untilhooks 790 catch native leaflets 136 and 138. Alternately, the release ofhooks 790 may be performed in left atrium 122, then pulled proximallyinto left ventricle 124 and then pushed back to catch native leaflets136 and 138. The initial release of hooks 790 may be accomplished withother types of sheaths, for example with a double proximal sheath with aslot or other opening in the inner sheath to allow hooks 790 to deployfirst. It should be noted that in the collapsed condition, hooks 790point toward inflow end 710, rather than toward outflow end 712. Inother words, hooks 790 (as well as flared portion 770) are folded towardleft atrium 122 during deployment, such that hooks 790 may graduallyexpand outwardly as the delivery sheath is slowly retracted. If, on theother hand, hooks 790 were delivered folded toward left ventricle 124,once the delivery sheath cleared hooks 790, the hooks would suddenlyflip nearly 180 degrees, possibly causing trauma to native valve annulusVA.

Once hooks 790 are in place, the distal portion of the split sheath maybe pushed distally to release flared portion 770. As it is released,flared portion 770 begins to expand on the atrial side of the nativevalve annulus VA. Prosthetic heart valve 700 is illustrated after fullrelease in FIG. 7B. The inclusion of smaller cells 754 a in ahigh-density arrangement in flared portion 770 allows for relativelygreater tissue ingrowth and also facilitates creating and maintainingthe flared shape of flared portion 770, which provides for betteralignment and sealing at inflow end 710 of stent 700.

With body 780 and hooks 790 in the expanded condition, hooks 790 hookaround the native anterior and posterior mitral valve leaflets, helpingsecure stent 700 in place. Because body 780 is generally comprised oflarger cells 754 b formed of thicker struts 752 instead of smaller cells754 a formed of thinner struts, body 780 is somewhat more rigid andfacilitates better anchoring by hooks 790. This better anchoring may bepartly due to the fact that hooks 790 are connected to body 780, and mayalso be formed of relatively thick struts 752 to provide additionalstrength. In addition, because hooks 790 point toward inflow end 710during delivery and deployment, stent 700 may be resheathed any timeprior to release of flared portion 770 into the expanded condition, forexample by pushing a proximal portion of a split sheath distally beforethe distal portion of the split sheath is released. If a double proximalsheath were used, stent 700 could be resheathed at any time prior torelease of the entire stent into the expanded condition.

Referring back to FIG. 7A, stent 700 may include one or more commissureattachment features (“CAFs”) 792 and one or more retention members 794as are known in the art. Each CAF 792 provides a site for the prostheticvalve leaflets to be attached to stent 700. Each retention member 794provides a feature for connecting stent 700 to the delivery device, theconnection being maintained until stent 700 is fully released from thedelivery device. It should further be noted that, although hooks 790 areshown as being formed integrally with stent 700, hooks 790 may be formedseparately of any one or a combination of a variety of materials,including for example Nitinol, polymers such as polyvinyl alcohol(“PVA”), and tissues such as bovine or porcine cardiac tissue.

FIG. 7C illustrates an alternate embodiment of stent 700′ of aprosthetic heart valve according to another embodiment of thedisclosure. (It should be noted in FIG. 7C that an opaque strip ofmaterial is positioned within stent 700′ to more clearly demonstratefeatures of the stent. This strip of material forms no part of stent700′ or the prosthetic valve incorporating the stent.) Stent 700′ hasfeatures in common with stent 700. For example, stent 700′ iscollapsible and expandable, has inflow end 710′ and outflow end 712′,and may be formed from biocompatible materials that are capable ofself-expansion. Stent 700′ may include a plurality of struts 752′ thatform cells connected to one another in one or more annular rows aroundthe stent. Stent 700′ includes flared portion 770′ at inflow end 710′.Flared portion 770′ extends radially outwardly in a direction away fromoutflow end 712′ and may include one or more circumferential rows ofcells 754′. Stent 700′ may also include a substantially cylindrical body780′ that extends from outflow end 712′ toward inflow end 710′. Body780′ may include one or more circumferential rows of cells 754′. Eachcell 754′ may be formed from a group of struts 752′ that defines ageneral diamond shape.

Stent 700′ may also include a portion with anchor members, such as hooks790′. Hooks 790′ may be formed of struts 752′ that extend radiallyoutwardly toward inflow end 710′, and then angle back such that theyextend generally parallel to a longitudinal axis of stent 700′. Hooks790′ may be integral with stent 700′, being formed from the same singlepiece of starting material, and may be connected to stent 700′ anywhereon body 780′. Hooks 790′ may be generally similar to hooks 790 of stent700, with at least two distinctions. First, as described above, ratherthan extend at a generally constant angle radially outward from body780′, hooks 790′ extend at a first angle and then angle back such that afree end of each hook 790′ is generally parallel to the longitudinalaxis of stent 700′. As illustrated in FIG. 7D, this configuration mayprovide a better clamping action of native valve leaflets 136 and 138.It should be noted that the free end of hooks 790′ need not be exactlyparallel to the longitudinal axis and variations from parallel mayexist. Second, the free end of hooks 790′ may be rounded or otherwisecurved. Compared to a free end with a sharp angle, hooks 790′ may beless traumatic to the native tissue.

Flared portion 770′ may also vary from flared portion 770 of stent 700,at least in that flared portion 770′ is not connected to body 780′ atthe tip of a cell 754′. Rather than being connected to the portion ofbody 780′ that is closest to inflow end 710′, flared portion 770′ isconnected to body 780′ farther toward outflow end 712′. In theillustrated embodiment, flared portion 770′ is connected to body 780′ ata point where two adjacent cells 754′ in the same circumferential rowmeet. This configuration results in some overlap in the longitudinaldirection of flared portion 770′ and body 780′. When implanted, asillustrated in FIG. 7D, flared portion 770′ makes contact with nativevalve annulus VA, while the points on body 780′ closest to inflow end710′ extend a distance into left atrium 122. Because structuresincluding a cuff and valve assembly (not illustrated in FIGS. 7C-D)would be attached to body 780′, retaining the cylindrical geometry ofbody 780′ near the point of contact between flared portion 770′ andnative valve annulus VA may help more evenly distribute the pressuresand forces exerted on stent 700′ during normal operation. The deliveryand deployment of a prosthetic heart valve incorporating stent 700′ maybe substantially the same as described above in relation to stent 700.

FIG. 8A illustrates a stent 800 of a prosthetic heart valve according toanother embodiment of the disclosure. Stent 800 is collapsible andexpandable for use in a prosthetic heart valve for replacing thefunction of the native mitral valve of a patient. In FIG. 8A, stent 800is illustrated in its expanded condition.

Stent 800 has inflow end 810 and outflow end 812, and may be formed frombiocompatible materials that are capable of self-expansion, such as, forexample, shape memory alloys including Nitinol. Stent 800 may include aplurality of struts 852 that form cells 854 connected to one another inone or more annular rows around the stent.

Stent 800 includes a substantially cylindrical body 870 and two anchorsections. The anchor sections may take the form of a firstcircumferential row of hooks 880 and a second circumferential row ofhooks 890. Each hook 880 in the first circumferential row has a firstend attached to inflow end 810 of stent 800 and a free end extendingradially outwardly and toward outflow end 812 of stent 800 in theexpanded condition. (It should be noted in FIG. 8A that an opaque stripof material is positioned between first circumferential row of hooks 880and body 870 to more clearly demonstrate their relative radialpositioning. This strip of material forms no part of stent 800 or theprosthetic valve incorporating the stent.) Each hook 890 in the secondcircumferential row has a first end attached to body 870 of stent 800 ata spaced distance from inflow end 810 and a free end extending radiallyoutwardly and toward outflow end 812 in the expanded condition.

When being used in a prosthetic heart valve for replacing the nativemitral valve of a patient, stent 800 is crimped to a collapsed conditionand positioned within a catheter or similar structure of a deliverydevice. In the collapsed condition, the free ends of hooks 880 in thefirst circumferential row and the free ends of hooks 890 in the secondcircumferential row all point toward outflow end 812 of stent 800. If atransfemoral or transaortic delivery route is used, once at the site ofimplantation, a sheath covering stent 800 may be retracted such thatoutflow end 812 of stent 800 expands first. As outflow end 812 of stent800 expands and the sheath is retracted further, hooks 890 in the secondcircumferential row are released from constraint. Upon furtherretraction of the sheath, the remainder of stent 800, along with hooks880 in the first circumferential row, are released from the constraintof the sheath and expand.

FIG. 8B illustrates stent 800 in its fully expanded state within nativemitral valve annuls VA. In particular, hooks 880 in the firstcircumferential row are positioned on, and in contact with, the atrialside of native valve annulus VA. Hooks 890 in the second circumferentialrow are positioned on, and in contact with, the ventricular side ofnative valve annulus VA. This positioning facilitates anchoring of stent800 in native valve annulus VA, and helps to prevent PV leak.

Because the free ends of hooks 880 and 890 are all pointed towardoutflow end 812 during deployment, stent 800 may be resheathed any timeprior to release of the entire stent into the expanded condition.Similarly, because of this orientation of hooks 880 and 890 duringdeployment, the transition of hooks 880 and 890 from the collapsedcondition to the expanded condition is relatively gradual, decreasingthe likelihood of trauma to native valve annulus VA during release ofstent 800 from the sheath. It should be understood that a similar resultmay be achieved with a transapical delivery route if a sheath with adistal pull-off is used. Further, other routes not specificallymentioned herein, such through the inferior vena cava, may be used withan appropriate sheath to allow the desired order of release andresheathing capabilities, as would be understood by one of ordinaryskill in the art.

Referring back to FIG. 8A, stent 800 may include one or more CAFs 892and one or more retention members 894 as are known in the art. It shouldbe noted that retention members 894 are on inflow end 810 in this casebecause inflow end 810 is intended to be released at the end ofdeployment. This is in contrast to retention members 794 of stent 700 inFIG. 7A, which are on outflow end 712 because outflow end 712 of stent700 is intended to be released at the end of deployment.

FIG. 9 illustrates stent 900 of a prosthetic heart valve according to afurther embodiment of the disclosure. Stent 900 is collapsible andexpandable for use in a prosthetic heart valve intended to replace thefunction of the native mitral valve of a patient. In FIG. 9, stent 900is illustrated as if it were cut longitudinally and laid out in a flat,expanded condition.

Stent 900 has inflow end 910 and outflow end 912 and may be formed frombiocompatible materials that are capable of self-expansion, such as, forexample, shape memory alloys including Nitinol. Stent 900 may include aplurality of struts 952 that form cells 954 connected to one another inone or more annular rows around the stent.

Stent 900 includes a substantially cylindrical body 970 and two anchorsections. The anchor sections may take the form of a firstcircumferential row of hooks 980 and a second circumferential row ofhooks 990. Each hook 980 in the first circumferential row has a firstend attached to inflow end 910 of stent 900 and a free end extendingradially outwardly and toward outflow end 912 of stent 900 when in theexpanded condition. Each hook 990 in the second circumferential row hasa first end attached to body 970 of stent 900 at a spaced distance frominflow end 910 and a free end extending radially outwardly and towardinflow end 910 of stent 900 when in the expanded condition. It should benoted that, when in the expanded condition, hooks 980 and 990 may extendgenerally perpendicular to stent body 970 or at an oblique angle towardseither inflow end 910 or outflow end 912. It should also be noted thateach circumferential row of hooks 980 or 990 need not be continuous. Forexample, groups of one, two, or more hooks 990 may be provided to anchorstent 900 to native anterior and posterior mitral valve leaflets, with anumber of cells 954 without hooks 990 being positioned between thegroups.

When used in a prosthetic heart valve intended to replace the nativemitral valve of a patient, stent 900 is crimped to a collapsed conditionand positioned within a catheter or similar structure of a deliverydevice. In the collapsed condition, the free ends of hooks 980 in thefirst circumferential row and the free ends of hooks 990 in the secondcircumferential row all point toward the center of stent 900. This maybe particularly useful when a split sheath is being used to deploy stent900.

Generally, a split sheath refers to a sheath that is configured to housestent 900 in a collapsed condition and a portion of the sheath housingthe stent may move distally with respect to the stent while theremainder of the sheath housing the stent may remain stationary or mayindependently move proximally with respect to the stent. With a splitsheath inflow end 910 may be exposed before or after outflow end 912. Inother words, distal movement of one portion of the sheath housing willexpose inflow end 910, while proximal movement of the remainder of thesheath housing will expose outflow end 912. Although hooks 980 and 990may be deployed in any desired order, it may be preferable to firstdeploy second circumferential row of hooks 990 in left ventricle 124 andthen push stent 900 such that hooks 990 engage native valve leaflets 136and 138. Once engaged, and first circumferential row of hooks 980 may bedeployed in left atrium 122 while keeping a portion of the distaldelivery sheath covering inflow end 910. Once proper positioning isverified, the distal sheath may be pushed beyond inflow end 910 and theproximal sheath may be pulled off the outflow end 912 to fully releasestent 900. When in the fully expanded condition, stent 900 may beanchored to the native mitral valve in a manner similar to thatillustrated in FIG. 8B. However, unlike other embodiments describedherein, the configurations of hooks 980 and 990 allow the entire stent900 to be resheathed prior to the full release of the stent when a splitsheath device is used for deployment.

FIG. 10 illustrates a stent 1000 of a prosthetic heart valve accordingto a further embodiment of the disclosure. Stent 1000 is collapsible andexpandable for use in a prosthetic heart valve for replacing thefunction of the native mitral valve of a patient. In FIG. 10, stent 1000is illustrated in the expanded condition.

Stent 1000 has inflow end 1010 and outflow end 1012 and may be formedfrom biocompatible materials that are capable of self-expansion, suchas, for example, shape memory alloys including Nitinol. Stent 1000 mayinclude a plurality of struts 1052 that form cells 1054 connected to oneanother in one or more annular rows around the stent.

Stent 1000 includes a substantially cylindrical body 1070 and two anchorsections. The anchor sections may take the form of a firstcircumferential row of hooks 1080 and a second circumferential row ofhooks 1090. Each hook 1080 in the first circumferential row has a firstend attached to inflow end 1010 of stent 1000 and a free end extendingradially outwardly. Each hook 1090 in the second circumferential row hasa first end attached to outflow end 1012 of stent 1000 and a free endextending radially outwardly. In the expanded condition, hooks 1080 and1090 may extend substantially perpendicularly to the central axis ofbody 1070 or, for each circumferential row, the hooks in thatcircumferential row may extend at an angle towards the hooks in theother circumferential row. Each hook 1080 may be a part of a single cell1054 that is also part of body 1070. Similarly, each hook 1090 may bepart of a single cell 1054 that is also part of body 1070. The firstcircumferential row of hooks 1080 may extend continuously around theperimeter of inflow end 1010. In other words, each cell 1054 at inflowend 1010 may form a hook 1080. However, it should be understood thathooks 1080 need not extend continuously around the perimeter of inflowend 1010 and cells 1054 not forming a hook may be interposed betweencells that do form hooks. The second circumferential row of hooks 1090is preferably not continuous. In other words, at least some cells 1054at outflow end 1012 preferably do not from a hook 1090. For example,cells 1054 terminating in a CAF 1094 preferably do not form a hook 1090,otherwise the ability to attach a prosthetic valve to stent 1000 couldbe hindered.

When used in a prosthetic heart valve to replace the native mitral valveof a patient, stent 1000 is crimped to a collapsed condition andpositioned within a catheter or similar structure of a delivery device.In the collapsed condition, the free ends of hooks 1080 in the firstcircumferential row point away from outflow end 1012 and the free endsof hooks 1090 in the second circumferential row point away from inflowend 1010.

Depending on the particular mode of delivery and sheath used to deploystent 1000, stent 1000 may be only partially resheathable. In otherwords, if the hooks in only one circumferential row have been deployedfrom the delivery device, stent 1000 may be resheathed to reposition itsassociated prosthetic valve. If, on the other hand, the hooks in bothcircumferential rows have been deployed from the delivery device, stent1000 may no longer be resheathed even if retention members 1094 arestill connected to the delivery device. Despite being only partiallyresheathable, the configuration of stent 1000 may provide a number ofbenefits. For example, stent 1000 generally has a less complex structurethan, for example, stents 700, 800, and 900, which may result insimplified manufacturing. Also, at least partly because hooks 1080 and1090 are portions of cells 1054 of body 1070, all cells 1000 of stent1050 may be arranged in a high-density format. The high-density formatmay provide, for example, a greater surface area of material to interactwith the native anatomy as well as for supporting a cuff, valves, and/orsealing materials attached thereto. In addition, when in the crimpedcondition, there is no overlap between either row of hooks andcylindrical body 1070, permitting a smaller crimp profile to beobtained. Similarly to stents 700, 800, and 900, once stent 1000 isproperly positioned in native valve annulus VA, hooks 1080 and 1090 mayfunction to both anchor stent 1000 in place and to help seal against PVleak.

FIG. 11 illustrates a prosthetic heart valve 1100 according to anotherembodiment of the disclosure. Prosthetic heart valve 1100 is collapsibleand expandable and designed to replace the function of the native mitralvalve of a patient. In FIG. 11, prosthetic heart valve 1100 isillustrated in the expanded condition.

Prosthetic heart valve 1100 may include wire-form stent 1150, which maybe formed from biocompatible materials that are capable ofself-expansion, such as, for example, shape memory alloys includingNitinol. Unlike other embodiments described herein, stent 1150 may beformed from a single wire 1152 shaped as desired, as opposed to, forexample, a single tube laser cut to a desired shape. In the illustratedembodiment, stent 1150 includes two anchor sections. In particular, theanchor sections may include a first series of hooks 1180 and a secondseries of hooks 1190. Each hook 1180 in the first series may extendradially outward from inflow end 1110 of stent 1150. Each hook 1190 inthe second series may extend radially outward from outflow end 1112 ofstent 1150. A free end of each hook 1190 may be bent back toward inflowend 1110.

Prosthetic heart valve 1100 may include a cuff 1164 attached to stent1150. Cuff 1164 may include a first generally flat portion 1164 a thatspans across and is attached to first series of hooks 1180. Preferably,hooks 1180 extend substantially in a continuous pattern around thecircumference of prosthetic heart valve 1100 to provide adequate supportfor first cuff portion 1164 a. When prosthetic heart valve 1100 isimplanted, first cuff portion 1164 a is positioned on the atrial side ofthe native valve annulus and may act as a sealing member similar tosealing members 480 and 580 of prosthetic heart valves 400 and 500,respectively. Cuff 1164 may include a second portion 1164 b projectingfrom flat portion 1164 a in the form of an annular wall surrounding anopening generally in the center of the flat portion. Second portion 1164b provides structure for the attachment of prosthetic leaflets toprosthetic heart valve 1100. When prosthetic heart valve 1100 isimplanted, second series of hooks 1190 may be positioned on theventricular side of the native mitral valve annulus, and may hook aroundthe native mitral valve leaflets to provide anchoring for prostheticheart valve 1100. With this configuration, two groups of hooks 1190corresponding to the positions of native mitral valve leaflets may besufficient for anchoring, without needing hooks 1190 to extend aroundthe entire circumference of stent 1150.

While prosthetic leaflets may be attached to cuff 1164 and stent 1150 toform a fully functioning prosthetic heart valve, cuff 1164 and stent1150 may be used in combination as a docking station in a two-stepdelivery system, similar to docking station 600 described above. If usedas a docking station, cuff 1164 and stent 1150 may be implanted in thenative valve annulus first, followed by the implantation of atraditional prosthetic heart valve or any prosthetic heart valvedescribed herein.

FIG. 12 is a side view of prosthetic heart valve 1200 according to afurther embodiment of the disclosure. Prosthetic heart valve 1200 is acollapsible prosthetic heart valve designed to replace the function ofthe native mitral valve of a patient. Prosthetic valve 1200 may besubstantially cylindrical, with inflow end 1210 and outflow end 1212.When used to replace native mitral valve 130, prosthetic valve 1200 mayhave a low profile so as not to interfere with atrial function in thenative valve annulus.

Prosthetic heart valve 1200 may include stent 1250, which may be formedfrom biocompatible materials that are capable of self-expansion, suchas, for example, shape memory alloys including Nitinol. Stent 1250 mayinclude a plurality of struts 1252 that form cells 1254 connected to oneanother in one or more annular rows around the stent.

Prosthetic heart valve 1200 may also include a valve assembly similar tothat described in connection with FIGS. 3A-B. The prosthetic leaflets ofthe valve assembly replace the function of native mitral valve leaflets136 and 138. That is, the leaflets coapt with one another to function asa one-way valve. The prosthetic leaflets may be attached to stent 1250at one or more CAFs 1294. Each CAF 1294 may be integral with stent 1250,for example by laser cutting the entire structure from a tube ofmaterial.

For prosthetic mitral valves, the stents generally include CAFs thatextend in the outflow direction and which are connected to a cell at theoutflow end of the stent. In other words, CAFs are generally positionedat an end of the stent. Due to this positioning, and due to the factthat the prosthetic leaflets are attached to the CAFs and are subjectedto forces, for example from restricting blood flow in the retrogradedirection, the CAFs are prone to deflect inwardly at times during normaloperation. This is particularly true when the mitral valve is closed andthe pressure in the left ventricle is greater than the pressure in theleft atrium.

As illustrated in FIG. 12, CAF 1294 is embedded within a cell 1254 ofstent 1250, rather than being positioned beyond outflow end 1212. Inother words, CAF 1294 is positioned between inflow end 1210 and outflowend 1212. CAF 1294 has a first end attached to struts 1252 and a secondfree end pointing toward inflow end 1210. This configuration may reducethe torque experienced by CAF 1294 due to the forces acting on theprosthetic leaflets attached to CAF 1294, thereby reducing thedeflection of CAF 1294 during normal operation. This, in turn, mayresult in better coaptation between the prosthetic leaflets and lessdeterioration of the valve.

As illustrated in FIG. 12, CAF 1294 is embedded within a cell 1254 ofstent 1250, rather than being positioned beyond outflow end 1212. Inother words, CAF 1294 is positioned between inflow end 1210 and outflowend 1212. CAF 1294 has a first end attached to struts 1252 and a secondfree end pointing toward inflow end 1210. This configuration may reducethe torque experienced by CAF 1294 due to the forces acting on theprosthetic leaflets attached to CAF 1294, thereby reducing thedeflection of CAF 1294 during normal operation. This, in turn, mayresult in better coaptation between the prosthetic leaflets and lessdeterioration of the valve.

FIG. 13 illustrates a stent 1300 of a prosthetic heart valve accordingto still another embodiment of the disclosure. Stent 1300 is collapsibleand expandable for use in a prosthetic heart valve intended to replacethe function of the native mitral valve of a patient. In FIG. 13, stent1300 is illustrated in its expanded condition.

Stent 1300 has inflow end 1310 and outflow end 1312, and may be formedfrom biocompatible materials that are capable of self-expansion, suchas, for example, shape memory alloys including Nitinol. Stent 1300 mayinclude a plurality of struts 1352 that form cells 1354 connected to oneanother in one or more annular rows around stent 1300.

Stent 1300 may be thought of as having an atrial portion 1370 and aventricular portion 1380. When implanted in native valve annulus VA,atrial portion 1370 of stent 1300 is positioned on the atrial side ofnative valve annulus VA, while ventricular portion 1380 of stent 1300 ispositioned on the ventricular side of native valve annulus VA. Atrialportion 1370 of stent 1300 has a generally bulbous shape and isconfigured to protrude farther into left atrium 122 than ventricularportion 1380 protrudes into left ventricle 124. The bulbous shape ofatrial portion 1370 provides anchoring of stent 1300, helping to resistthe migration of the stent into left ventricle 124. The bulbous shape ofatrial portion 1370 and the extent of anchoring in left atrium 122reduce the radial forced needed at native valve annulus VA to keep stent1300 in place. As a result, ventricular portion 1380 need only extendminimally into left ventricle 124, which may reduce interference withchordae tendineae 134. For example, as illustrated, less than a full rowof cells 1354 is configured to be positioned in left ventricle 124 whenstent 1300 is implanted in native valve annulus VA.

Various modifications may be made to the embodiments disclosed hereinwithout departing from the scope of the disclosure. For example,although stents and prosthetic heart valves are generally described forreplacement of the mitral other bicuspid valves, variations may be madeto these devices to replace tricuspid valves. Thus, the prostheticvalves may be provided with three leaflets, or more or less leaflets asdesired. Similarly, although generally described as self-expandingprosthetic heart valves or stents, the principles described herein arealso applicable to prosthetic valves that are not self-expanding, suchas balloon expandable prosthetic valves.

According to one embodiment of the disclosure, a prosthetic heart valvecomprises: a stent having an inflow end, an outflow end, a centerportion between the inflow end and the outflow end, a collapsedcondition, and an expanded condition; a collapsible and expandable valveassembly disposed within the stent and having a plurality of leaflets; afirst annular sealing member coupled to the inflow end; and a secondannular sealing member coupled to the outflow end; and/or

-   -   the first and second sealing members each have a diameter        greater than a diameter of the stent when the stent is in the        expanded condition; and/or    -   the stent is substantially cylindrical in the expanded        condition; and/or    -   the first sealing member has a substantially planar        configuration when the stent is in the expanded condition;        and/or    -   the inflow end and the outflow end of the stent each has a        diameter greater than a diameter of the center portion of the        stent when the stent is in the expanded condition; and/or    -   the first sealing member is substantially nonplanar when the        stent is in the expanded condition; and/or    -   an outer perimeter of the first sealing member is closer to the        outflow end than an inner perimeter of the first sealing member        when the stent is in the expanded condition.

According to another embodiment of the disclosure, a stent having anexpanded condition and a collapsed condition comprises: a substantiallycylindrical body having a first end and a second end; a flared portioncoupled to the first end of the body and extending radially outwardlyfrom the body and away from the second end of the body when the stent isin the expanded condition; and a plurality of anchor members each havinga first end coupled to the body and a second free end extending radiallyoutwardly from the body and toward the first end of the body when thestent is in the expanded condition, wherein the flared portion and thesecond free ends of the anchor members are configured to extend awayfrom the second end of the body when the stent is in the collapsedcondition; and/or

-   -   the flared portion and the body are each formed of a plurality        of struts that form cells having an area, the area of each cell        of the body being greater than the area of each cell of the        flared portion when the stent is in the expanded condition;        and/or    -   the flared portion and the body are each formed of a plurality        of struts having a thickness, the thickness of the struts        forming the flared portion being less than the thickness of the        struts forming the body.

According to a further embodiment of the disclosure a stent having anexpanded condition and a collapsed condition comprises: a substantiallycylindrical center body having a first end and a second end; a firstplurality of anchor members each having a first end coupled to the firstend of the body and a second free end extending radially outwardly fromthe body and toward the second end of the body when the stent is in theexpanded condition; and a second plurality of anchor members each havinga first end coupled to the body and a second free end extending radiallyoutwardly from the body and toward the second end of the body when thestent is in the expanded condition, wherein the first and secondplurality of anchor members are configured to extend toward the secondend of the body when the stent is in the collapsed condition.

According to still another embodiment of the disclosure, a stent havingan expanded condition and a collapsed condition comprises: asubstantially cylindrical center body having a first end and a secondend; a first plurality of anchor members each having a first end coupledto the body and a second free end extending radially outwardly from thebody and toward the first end of the body when the stent is in theexpanded condition; and a second plurality of anchor members each havinga first end coupled to the first end of the body and a second free endextending radially outwardly from the body and toward the second end ofthe body when the stent is in the expanded condition, wherein the firstplurality of anchor members extend toward the first end of the body andthe second plurality of anchor members extend toward the second end ofthe body when the stent is in the collapsed condition; and/or

-   -   the second plurality of anchor members includes a first group of        anchor members and a second group of anchor members, the first        group being configured to engage a native posterior mitral valve        leaflet and the second group being configured to engage a native        anterior mitral valve leaflet when the stent is implanted in a        native mitral valve annulus of a patient.

According to yet another embodiment of the disclosure, a stent having anexpanded condition and a collapsed condition comprises: a substantiallycylindrical center body having a first end, a second end, and alongitudinal axis extending between the first end and the second end; afirst plurality of anchor members each having a first end coupled to thebody and a second free end extending radially outwardly from the bodyand substantially perpendicular to the longitudinal axis of the bodywhen the stent is in the expanded condition; and a second plurality ofanchor members each having a first end coupled to the body and a secondfree end extending radially outwardly from the body and substantiallyperpendicular to the longitudinal axis of the body when the stent is inthe expanded condition, wherein the first plurality of anchor membersextend away from the second end of the body and the second plurality ofanchor members extend away from the first end of the body when the stentis in the collapsed condition; and/or

-   -   a plurality of struts forming a first circumferential row of        cells and a second circumferential row of cells, wherein each of        the first plurality of anchor members is at least partially        formed from one of the cells in the first circumferential row        and each of the second plurality of anchor members is at least        partially formed from one of the cells in the second        circumferential row.

According to yet a further embodiment of the disclosure, a prostheticheart valve comprises: a stent having an inflow end, an outflow end, acollapsed condition, and an expanded condition, the stent being formedfrom wire and having a first series of hooks and a second series ofhooks; and a cuff coupled to the stent, wherein, when the stent is inthe expanded condition, each hook of the first series extends radiallyoutwardly from the stent at the inflow end and each hook of the secondseries includes a first portion that extends radially outwardly from thestent at the outflow end and a second portion that extends toward theinflow end; and/or

-   -   the cuff has a first substantially flat portion that spans        across and is coupled to the first series of hooks.

According to an even further embodiment of the disclosure, a prostheticheart valve comprises: a stent having an inflow end, an outflow end, acollapsed condition, and an expanded condition, the stent being formedof a plurality of struts; a collapsible and expandable valve assemblydisposed within the stent and having a plurality of leaflets; and acommissure attachment feature attached to at least one of the pluralityof struts and positioned between the inflow end and the outflow end whenthe stent is in the expanded condition; and/or

-   -   the commissure attachment feature has a first end attached to at        least one of the plurality of struts and a second free end        extending toward the inflow end when the stent is in the        expanded condition.

It will be appreciated that the various dependent claims and thefeatures set forth therein can be combined in different ways thanpresented in the initial claims. It will also be appreciated that thefeatures described in connection with individual embodiments may beshared with others of the described embodiments.

1. A prosthetic heart valve, comprising: a stent having an inflow end,an outflow end, a center portion between the inflow end and the outflowend, a collapsed condition, and an expanded condition; a collapsible andexpandable valve assembly disposed within the stent and having aplurality of leaflets; a first annular sealing member coupled to theinflow end; and a second annular sealing member coupled to the outflowend.
 2. The prosthetic heart valve of claim 1, wherein the first andsecond sealing members each have a diameter greater than a diameter ofthe stent when the stent is in the expanded condition.
 3. The prostheticheart valve of claim 2, wherein the stent is substantially cylindricalin the expanded condition.
 4. The prosthetic heart valve of claim 2,wherein the first sealing member has a substantially planarconfiguration when the stent is in the expanded condition.
 5. Theprosthetic heart valve of claim 2, wherein the inflow end and theoutflow end of the stent each has a diameter greater than a diameter ofthe center portion of the stent when the stent is in the expandedcondition.
 6. The prosthetic heart valve of claim 2, wherein the firstsealing member is substantially nonplanar when the stent is in theexpanded condition.
 7. The prosthetic heart valve of claim 6, wherein anouter perimeter of the first sealing member is closer to the outflow endthan an inner perimeter of the first sealing member when the stent is inthe expanded condition.
 8. The prosthetic heart valve of claim 6,wherein an outer perimeter of the second sealing member is closer to theinflow end than an inner perimeter of the second sealing member when thestent is in the expanded condition.
 9. A stent having an expandedcondition and a collapsed condition, comprising: a substantiallycylindrical body having a first end and a second end; a flared portioncoupled to the first end of the body and extending radially outwardlyfrom the body and away from the second end of the body when the stent isin the expanded condition; and a plurality of anchor members each havinga first end coupled to the body and a second free end extending radiallyoutwardly from the body and toward the first end of the body when thestent is in the expanded condition, wherein the flared portion and thesecond free ends of the anchor members are configured to extend awayfrom the second end of the body when the stent is in the collapsedcondition.
 10. The stent of claim 9, wherein the flared portion and thebody are each formed of a plurality of struts that form cells having anarea, the area of each cell of the body being greater than the area ofeach cell of the flared portion when the stent is in the expandedcondition.
 11. The stent of claim 9, wherein the flared portion and thebody are each formed of a plurality of struts having a thickness, thethickness of the struts forming the flared portion being less than thethickness of the struts forming the body.
 12. A stent having an expandedcondition and a collapsed condition, comprising: a substantiallycylindrical center body having a first end and a second end; a firstplurality of anchor members each having a first end coupled to the firstend of the body and a second free end extending radially outwardly fromthe body and toward the second end of the body when the stent is in theexpanded condition; and a second plurality of anchor members each havinga first end coupled to the body and a second free end extending radiallyoutwardly from the body and toward the second end of the body when thestent is in the expanded condition, wherein the first and secondplurality of anchor members are configured to extend toward the secondend of the body when the stent is in the collapsed condition.
 13. Astent having an expanded condition and a collapsed condition,comprising: a substantially cylindrical center body having a first endand a second end; a first plurality of anchor members each having afirst end coupled to the body and a second free end extending radiallyoutwardly from the body and toward the first end of the body when thestent is in the expanded condition; and a second plurality of anchormembers each having a first end coupled to the first end of the body anda second free end extending radially outwardly from the body and towardthe second end of the body when the stent is in the expanded condition,wherein the first plurality of anchor members extend toward the firstend of the body and the second plurality of anchor members extend towardthe second end of the body when the stent is in the collapsed condition.14. The stent of claim 13, wherein the second plurality of anchormembers includes a first group of anchor members and a second group ofanchor members, the first group being configured to engage a nativeposterior mitral valve leaflet and the second group being configured toengage a native anterior mitral valve leaflet when the stent isimplanted in a native mitral valve annulus of a patient.
 15. A stenthaving an expanded condition and a collapsed condition, comprising: asubstantially cylindrical center body having a first end, a second end,and a longitudinal axis extending between the first end and the secondend; a first plurality of anchor members each having a first end coupledto the body and a second free end extending radially outwardly from thebody and substantially perpendicular to the longitudinal axis of thebody when the stent is in the expanded condition; and a second pluralityof anchor members each having a first end coupled to the body and asecond free end extending radially outwardly from the body andsubstantially perpendicular to the longitudinal axis of the body whenthe stent is in the expanded condition, wherein the first plurality ofanchor members extend away from the second end of the body and thesecond plurality of anchor members extend away from the first end of thebody when the stent is in the collapsed condition.
 16. The stent ofclaim 15, further comprising: a plurality of struts forming a firstcircumferential row of cells and a second circumferential row of cells,wherein each of the first plurality of anchor members is at leastpartially formed from one of the cells in the first circumferential rowand each of the second plurality of anchor members is at least partiallyformed from one of the cells in the second circumferential row.
 17. Aprosthetic heart valve, comprising: a stent having an inflow end, anoutflow end, a collapsed condition, and an expanded condition, the stentbeing formed from wire and having a first series of hooks and a secondseries of hooks; and a cuff coupled to the stent, wherein, when thestent is in the expanded condition, each hook of the first seriesextends radially outwardly from the stent at the inflow end and eachhook of the second series includes a first portion that extends radiallyoutwardly from the stent at the outflow end and a second portion thatextends toward the inflow end.
 18. The prosthetic heart valve of claim17, wherein the cuff has a first substantially flat portion that spansacross and is coupled to the first series of hooks.
 19. A prostheticheart valve, comprising: a stent having an inflow end, an outflow end, acollapsed condition, and an expanded condition, the stent being formedof a plurality of struts; a collapsible and expandable valve assemblydisposed within the stent and having a plurality of leaflets; and acommissure attachment feature attached to at least one of the pluralityof struts and positioned between the inflow end and the outflow end whenthe stent is in the expanded condition.
 20. The prosthetic heart valveof claim 19, wherein the commissure attachment feature has a first endattached to at least one of the plurality of struts and a second freeend extending toward the inflow end when the stent is in the expandedcondition.